FIG. 16 is a top plan view showing a film substrate of a prior art semiconductor device before molding. In the figure, reference numeral 1 designates an insulating film substrate, comprising, for example, polyimide having a thickness of 100 microns and dimensions of 6 mm.times.8 mm, and numeral 2 designates a semiconductor chip for use at high frequencies, for example, an amplifier which is several millimeters along each edge. Numerals 3a to 3e designate upper metal wiring patterns having a thickness of approximately 10 microns on the insulating film substrate 1, numeral 3a designates a grounding pad of the high frequency semiconductor chip 2, numeral 3b designates an external lead for exchanging signals with the high frequency semiconductor chip 2, numeral 3c designates a meandering type inductor for adjusting inductance when a bias voltage is applied to the high frequency semiconductor chip 2, numeral 3d designates a spiral type inductor similarly for adjusting inductance when bias voltage is applied to the high frequency semiconductor chip 2, and numeral 3e designates auxiliary wiring connected to the spiral type inductor 3d via a through hole described below. The upper metal wiring patterns 3b to 3d are respectively connected to the high frequency semiconductor chip 2 by wire 6 of gold or the like. Numeral 4 designates a through hole formed in the insulating film substrate 1 electrically connecting a lower metal wiring pattern 5 formed on the rear surface of the film substrate 1 to the upper metal wiring patterns 3 via a conductive material filling in the through hole 4, where an end part of the spiral type inductor 3d is connected to the auxiliary wiring 3e via the through holes 4 and the lower metal wiring pattern 5.
FIG. 17 is a cross section taken along a line A--A' of FIG. 16 showing a semiconductor device after molding. In the figure, numeral 8 designates a molding material for which resin is generally employed. Generally, the high frequency semiconductor chip 2 and the upper metal wiring pattern (grounding pad) 3a are die-bonded with solder or the like. A grounding conductive layer (which is not shown in the figure) on the rear surface of the high frequency semiconductor chip 2 is electrically connected to the upper metal wiring pattern (grounding pad) 3a. Further, numeral 4a designates a conductive material filling in the through hole 4.
Next, description is given of the operations.
In a semiconductor device operating at high frequencies such as in a microwave band, in general, since wires serve as distributed constant lines, the wires themselves operate as a passive circuit. Further, since the device operates at high frequencies, an inductor of minute inductance (approximately several nH) is often employed. In other words, the upper metal wiring patterns 3c and 3d on the film substrate 1 in FIG. 16 respectively serve as the meandering type inductor and the spiral type inductor, when a bias voltage is applied to the high frequency semiconductor chip 2 which is the amplifier. Since a passive circuit of wires is generally large as illustrated in FIG. 16, a package which is obtained by molding this passive circuit is also large.
As the prior art device is constructed as described above, the package is unfavorably oversized, resulting in an obstacle to miniaturization of a system including the package.